【单选题】一台光盘驱动器,正常正常使用一段时间后出现严重挑盘现象,则可能的故障原因是
【单选题】What happens at the end of the baseball season?_________
A.
People talk only about football games.
B.
Many baseball fans become members of top teams.
C.
A lot of people join in the games.
D.
Two top teams play a wonderful baseball game against each other.
【简答题】如图1,在平面直角坐标系中,抛物线y=- 5 6 x 2 + 13 6 x+c与y轴交于点D,与x轴负半轴交于点B(-1,0),直线y= 1 2 x+b与抛物线交于A、B两点.作△ABD的外接圆⊙M交x轴正半轴于点C,连结CD交AB于点E. (1)求b、c的值; (2)求:①点A的坐标;②∠AEC的正切值; (3)将△BOD绕平面内一点旋转90°,使得该三角形的对应顶点中的两个点落在已知抛物线上(...
【单选题】一台光盘驱动器,正常使用一段时间后出现严重挑盘现象,则可能的故障原因时( )(单选)
【简答题】Chapter 1: What happens at the beginning, in the middle, and at the end of the story?